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| A trait that increases the ability of an individual to survive and reproduce compared to individuals without the trait. |
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The smallest particle of an element that retains the properties of the element.
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Literally, "self-feeder" normally, a photosynthetic organism, a producer.
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The method of naming organisms by genus and species, often called the scientific name, usually Latin Words or words derived from Latin.
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| The diversity of living organisms, measured as the variety of different species, the variety of different alleles in species' gene pools, or the variety of different communities and nonliving environments in an ecosystem or in the entire biosphere. |
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| The smallest unit of life, consisting, at a minimum, of an outer membrane that encloses a watery medium containing organic molecules, including genetic material composed of DNA. |
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| The scientific theory stating that every living organism is made up of one or more cells; cells are the functional units of all organisms; and all cells arise from preexisting cells. |
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| A DNA double helix together with proteins that help to organize and regulate the use of DNA. |
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| All the interacting populations in an ecosystem. |
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| In the scientific method, a decision about the validity of a hypothesis, made on the basis of experiments or observations. |
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| That portion of an experiment in which all possible variables are held constant; in contrast to the "experimental" portion, in which a particular variable is altered. |
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| Cytoplasm- All of the material contained within the plasma membrane of a cell, exclusive of the membrane. |
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| Deoxyribonucleic acid (DNA) |
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Definition
| A molecule composed of deoxyribose nucleotides; contains the genetic information of all living things. |
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| The broadest category for classifying organisms; organisms are classified into three domains: Bacteria, Archaea, and Eukarya. |
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| A substance that cannot be broken down, or converted, to a simpler substance by ordinary chemical means. |
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| Referring to cells of organisms of the domain Eukarya (plants, animals, fungi, and protists). Eukaryotic cells had genetic material enclosed within a membrane-bound nucleus and contain other organelles. |
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| The descent of modern organisms, with modification, of preexisting life forms; the theory that all organisms are related and have changed over time. |
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| In the scientific method, the use of carefully controlled observations or manipulations to test the predictions generated by a hypothesis. |
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| The unit of hereditary; a segment of DNA located at a particular place on a chromosome the encodes the information for the amino acid sequence of a protein and, hence, particular traits. |
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| The maintenance of the relatively constant internal environment that is required for the optimal functioning of cells. |
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| In the scientific method, a supposition based on previous observations that is offered as an explanation for an observed phenomenon and is used as the basis for further observations or experiments. |
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| The second broadest taxonomic category, consisting of related phyla. Related kingdoms make up a domain. |
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| The sum of all chemical reactions that occur within a single cell or within all the cells of a multicellular organism. |
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| Many celled; most members of the kingdoms Fungi, Plantae, and Animalia are this, with intimate cooperation among cells. |
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| A change in the base sequence of DNA in a gene; often used to refer to a genetic change that is significant enough to alter the appearance or function of the organism. |
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| The unequal survival and reproduction of organisms with different phenotypes, caused by environmental forces. |
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| The central region of an atom, consisting of protons and neutrons. |
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| The membrane-bound organelle of eukaryotic cells that contains the cells genetic material. |
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| A substance acquired from the environment and needed for the survival, growth, and development of an organism. |
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| In the scientific method, the recognition of and a statement about a specific phenomenon, usually leading to the formulation of a question about the phenomenon. |
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| A structure (such as the liver, kidney, or skin) composed of two or more distinct tissue types that function together. |
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| A membrane-enclosed structure found inside a eukaryotic cell that performs a specific function. |
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| A molecule that contains both carbon and hydrogen. |
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| An individual living thing. |
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| Two or more organs that work together to perform a specific function; for example, the digestive system. |
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| The complete series of chemical reactions in which the energy of light is used to synthesize high-energy organic molecules, usually carbohydrates, from low energy inorganic molecules, usually carbon dioxide and water. |
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| The outer membrane of a cell, composed of a bilayer phospholipids in which proteins are embedded. |
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| All the members of a particular species within an ecosystem, found in the same time and place and actually or potentially interbreeding. |
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| In the scientific method, a statement describing an expected observation or the expected outcome of an experiment, assuming that a specific hypothesis is true. |
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| Referring to the cells of the domains Bacteria or Archaea. Prokaryotic cells have genetic material that is not enclosed in a membrane bound nucleus; they also lack other membrane-bound organelles. |
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| A rigorous procedure for making observations of specific phenomena and searching for the order underlying those phenomena. |
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| A general explanation of natural phenomena developed through extensive and reproducible observations; more general and reliable than a hypothesis. |
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| The basic unit of taxonomic classification, consisting of a population or group of populations that evolves independently of other populations. |
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| A group of (normally similar) cells that together carry out a specific function; may also include extracellular material produced by its cells. |
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| Single-celled; most members of the domains Bacteria and Archaea and the kingdom Protista are considered this. |
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| A factor in a scientific experiment that is deliberately manipulated in order to test a hypothesis. |
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| A substance that releases hydrogen ions (H+) into a solution; a solution with a pH less than 7. |
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| Referring to a solution with an H+ concentration exceeding that of OH-; referring to a substance that releases H+. |
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| Any molecule that reacts with free radicals, neutralizing their ability to damage biological molecules. Vitamins C and E are good dietary examples |
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| The number of protons in the nuclei of all atoms of a particular element. |
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| A substance capable of combining with and neutralizing H+ ions in a solution; a solution with a pH greater than 7. Example: In DNA, they are Adenine, Guanine, Cytosine, and Thymine. |
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Definition
| Referring to a solution with an H+ concentration less than that of OH-; referring to a substance that combines with H+. |
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| A compound that minimizes changes in pH by reversibly taking up or releasing H+ ions. |
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| An attraction between two atoms or molecules that tends to hold them together. Types of bonds include covalent, ionic, and hydrogen. |
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| The process that forms and breaks chemical bonds that hold atoms together in molecules. |
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| The tendency of the molecules of a substance to stick together. |
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| A substance whose molecules are formed by different types of atoms; can be broken into its constituent elements by chemical means. |
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| A chemical bond between atoms in which electrons are shared. |
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| A subatomic particle, found in an electron shell outside the nucleus of an atom, that bears a unit of negative charge and very little mass. |
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| A region in an atom within which electrons orbit; each shell corresponds to a fixed energy level at a given distance from the nucleus. |
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| A molecule containing an atom with an unpaired electron, which makes it highly unstable and reactive with nearby molecules. By removing an electron from the molecule it attacks, it creates a new free radical and begins a chain reaction that can lead to the destruction of biological molecules crucial to life. |
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| The weak attraction between a hydrogen atom that bears a partial positive charge (due to polar covalent bonding with another atom) and another atom (oxygen, nitrogen, or fluorine) that bears a partial negative charge. |
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| Pertaining to molecules that dissolve readily in water, or to molecules that form hydrogen bonds with water; polar. |
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| Pertaining to molecules that do not dissolve in water or form hydrogen bonds with water; nonpolar. |
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| The tendency for hydrophobic molecules to cluster together when immersed in water. |
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| A charged atom or molecule; and atom or molecule that has either an excess of electrons (negatively charged) or has lost electrons (positively charged.) |
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| A chemical bond formed by the electrical attraction between positively and negatively charged ions. |
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| A particle composed of one or more atoms held together by chemical bonds; the smallest particle of a compound that displays all the properties of a compound. |
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| A subatomic particle that is found in the nuclei of atoms, bears no charge, and has a mass approximately equal to that of a proton. |
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| A covalent bond with equal sharing of electrons. |
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| A scale, with values from 0 to 14, used for measuring the relative acidity of a solution. at pH7 a solution is neutral, 0-7 is acidic, and pH 7-14 is basic; each unit of the scale represents a tenfold change in H+ concentration. |
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Definition
| A covalent bond with unequal sharing of electrons, such that one atom is relatively negative and the other is relatively positive. |
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Definition
| A subatomic particle that is found in the nuclei of atoms; it bears a unit of positive charge, has a relatively large mass roughly equal to that of a neutron. |
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| A liquid capable of dissolving (uniformly dispersing) other substances in itself. Example: Water, acids. |
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Definition
| The property of liquids to resist penetration by objects at its interface with the air, due to cohesion between the molecules of the liquid. |
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| Adenosine Triphosphate (ATP) |
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Definition
| A molecule composed of the sugar ribose, the base adenine, and three phosphate groups; the major energy carrier in cells. The last two phosphate groups are attached by "high-energy" bonds. |
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Definition
| The individual subunit of which proteins are made, composed a central carbon atom bonded to an amino group (-NH2), a carboxyl group (-COOH), a hydrogen atom, and a variable group of atoms denoted by the letter R. |
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Definition
| A compound composed of carbon, hydrogen, and oxygen, with the approximate chemical formula (CH20)n; includes sugars, starches, and cellulose. |
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Definition
| An insoluble carbohydrate composed of glucose subunits; forms the cell wall of plants. |
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Definition
| A compound found in the cell walls of fungi and the exoskeletons of insects and some other arthropods; composed of chains of nitrogen-containing, modified glucose molecules. |
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Definition
| A chemical reaction in which two molecules are joined by a covalent bond with the simultaneous removal of a hydrogen from one molecule and and a hydroxyl group from the other, forming water; the reverse of hydrolysis. |
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| A carbohydrate formed by the covalent bonding of two monosaccharides. |
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| A biological catalyst, usually a protein, that speeds up the rate of specific biological reactions. |
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| An organic molecule composed of a long chain of carbon atoms, with a carboxylic acid (COOH) group at one end; may be saturated (all single bonds between the carbon atoms) or unsaturated (one or more double bonds between the carbon atoms). |
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Definition
| One of several groups of atoms commonly found in an organic molecule, including hydrogen, hydroxyl, amino, carboxyl, and phosphate groups, that determine the characteristics and chemical reactivity of the molecule. |
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| The most common monosaccharide, with the molecular formula C6H12O6; most polysaccharides, including cellulose, starch, and glycogen, are made of subunits of this, covalently bonded together. |
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Definition
| A three-carbon alcohol to which fatty acids are covalently bonded to make fats and oils. |
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Definition
| A highly branched polymer of glucose that is stored by animals in the muscles and liver and metabolized as a source of energy. |
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| A coiled, springlike secondary structure of a protein. |
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Definition
| Describing any molecule that does not contain both carbon and hydrogen. |
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Definition
| One of a number of organic molecules containing large non-polar regions composed solely of carbon and hydrogen, which makes this hydrophobic and insoluble in water; includes oils, fats, waxes, phospholipids, and steroids. |
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Definition
| A small organic molecule, several of which may be bonded together to form a chain called a polymer. |
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Definition
| The basic molecular unit of all carbohydrates, normally composed of a chain of carbon atoms bonded to hydrogen and hydroxyl groups. |
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Definition
| An organic molecule composed of nucleotide subunits; the two common types of this are RNA and DNA. |
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Definition
| A subunit of which nucleic acids are composed; a phosphate group bonded to a sugar (deoxyribose in DNA), which is in turn, bonded to a nitrogen- containing bas (adenine, guanine, cytosine, or thymine in DNA.) |
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Definition
| Describing a molecule that contains both carbon and hydrogen. |
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Definition
| The covalent bond between the nitrogen of the amino group of one amino acid and the carbon of the carboxyl group of a second amino acid, joining the two amino acids together in a peptide or protein. |
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Definition
| A lipid consisting of glycerol bonded to two fatty acids and one phosphate group, which bears another group of atoms, typically charged and containing nitrogen. |
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Definition
| A form of secondary structure exhibited by certain proteins, such as silk, in which many protein chains lie side by side, with hydrogen bonds holding adjacent chains together. |
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Definition
| A molecule composed of three or more (perhaps thousands) smaller units called monomers, which may be identical (monomers of starch) or different (amino acids of a protein.) |
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Definition
| A large carbohydrate molecule composed of branched or unbranched chains of repeating monosaccharide subunits, normally glucose or modified glucose molecules; includes starches, cellulose, and glycogen. |
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Definition
| The amino acid sequence of a protein. |
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Definition
| A polymer composed of amino acids joined by a peptide bond. |
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Definition
| The complex three-dimensional structure of a protein consisting of more than one peptide chain. |
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Definition
| A molecule composed of ribose nucleotides, each of which consists of a phosphate group, the sugar ribose, and one of the bases adenine, cytosine, guanine, or uracil; involved in converting the information in DNA into protein; also the genetic material of some viruses. |
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Definition
| Referring to a fatty acid with as many hydrogen atoms as possible bonded to the carbon backbone. |
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Definition
| A repeated, regular structure assumed by a protein chain, held together by hydrogen bonds (a helix). |
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Definition
| A polysaccharide that is composed of branched or unbranched chains of glucose molecules; used by plants as a carbohydrate-storage molecule. |
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Definition
| A lipid consisting of four fused carbon rings, with various functional groups attached. |
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Definition
| A simple carbohydrate molecule, either a monosaccharide or disaccharide. |
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Definition
| The complex three-dimentional structure of a single peptide chain; held in place by disulfide bonds between cysteines. |
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Definition
| A lipid composed of three fatty-acid molecules bonded to a single glycerol molecule. |
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Definition
| Referring to a fatty acid with fewer than the maximum number of hydrogen atoms bonded to its carbon backbone. |
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| One of life's three domains; consists of prokaryotes that are only distantly related to members of the domain Archaea. |
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Definition
| In animal cells, a short, barrel-shaped ring consisting of nine microtubule triplets; a pair of centrioles is found near the nucleus and may play a role in the organization of the spindle; these also give rise to the basal bodies at the base of each cilium and flagellum that give rise to the microtubules of cilia and flagella. |
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Definition
| A pigment found in chloroplasts that captures light energy during photosynthesis; this absorbs violet, blue, and red light but reflects green light. |
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Definition
| The organelle in plants and plantlike protists that is the site of photosynthesis; surrounded by a double membrane and containing an extensive internal membrane system that bears chlorophyll. |
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Definition
| The complex of DNA and proteins that makes up eukaryotic chromosomes. |
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Definition
| A short, hair-like, motile projection from the surface of certain eukaryotic cells that contains microtubules in a 9+2 arrangement. The movement of these may propel cells through a fluid medium or move fluids over a stationary surface layer of cells. |
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Definition
| All of the material contained within the plasma membrane of a cell, exclusive of the nucleus. |
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Definition
| A network of protein fibers in the cytoplasm that gives shape to a cell, holds a moves organelles, and is typically involved in cell movement. |
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Definition
| The liquid found inside cells. |
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| Endoplasmic Reticulum (smooth and rough) |
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Definition
| A system of membranous tubes and channels in eukaryotic cells; the site of most protein and lipid synthesis. |
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Definition
| The hypothesis that certain organelles, especially chloroplasts and mitochondria, arose as mutually beneficial associations between the ancestors of eukaryotic cells and captured bacteria that lived within the cytoplasm of the pre-eukaryotic cell. |
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Definition
| A long, hair-like, motile extension of the plasma membrane; in eukaryotic cells, it contains microtubules arranged in a 9+2 pattern. The movement of these propel some cells through fluid. |
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Definition
| A stack of membranous sacs, found in most eukaryotic cells, that is the site of processing and separation of membrane components and secretory materials. |
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Definition
| Part of the cytoskeleton of eukaryotic cells that is composed of several types proteins and probably functions mainly for support. |
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Definition
| A membrane-bound organelle containing intracellular digestive enzymes. |
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Definition
| Part of the cytoskeleton of eukaryotic cells that is composed of the proteins actin and (in some cases) myosin; functions in the movement of cell organelles, locomotion by extension of the plasma membrane, and sometimes contraction of entire cells. |
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Definition
| A hollow, cylindrical strand, found in eukaryotic cells, this is composed of the protein tubulin; part of the cytoskeleton used in the movement of organelles, cell growth, and the construction of cilia and flagella. |
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Definition
| An organelle, bounded by two membranes, that is the site of reactions of aerobic metabolism. |
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Definition
| The double-membrane system surrounding the nucleus of eukaryotic cells; the outer membrane is typically continuous with the endoplasmic reticulum. |
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Definition
| The location of the genetic material in prokaryotic cell; not membraned enclosed. |
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Definition
| The region of the eukaryotic nucleus that is engaged in ribosome synthesis; consists of the genes encoding ribosomal RNA, newly synthesized ribosomal RNA, and ribosomal proteins. |
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Definition
| n plant cells, an organelle bounded by two membranes that may be involved in photosynthesis (chloroplasts), pigment storage, or food storage. |
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Definition
| A complex consisting of two subunits, each composed of ribosomal RNA and protein, found in the cytoplasm of cells or attached to the endoplasmic reticulum, that is the site of protein synthesis, during which the sequence of bases of messenger RNA is translated into the sequence of amino acids in a protein. |
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Definition
| A vesicle that is typically large and consists of a single membrane enclosing a fluid filled space. |
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Definition
| A small, membrane-bound sac within the cytoplasm. |
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